Tomas Muñoz puts down his pencil as he looks at his math homework. The third-grader raises his hands and begins counting on his fingers. Something finally clicks and he writes down his answer to the subtraction problem.

Head instructor Ryan Jimenez comes over to review his work. Everything checks out, and Tomas thrusts his fists triumphantly into the air. Jimenez pulls out two reward cards, known as stamps.

“Did you think that was easy?” he asks. “Yeah,” the boy replies sheepishly.

Everything seems a bit easier since Tomas began tutoring sessions at Mathnasium in Denton about a year ago. With more than 700 locations around the world, the math-centric learning center helps second- through 12th-graders tackle what 37 percent of students say is their toughest subject in school, according to a Gallup poll.

“It makes us sad because you’ll have this bright kid who reads at a fifth-grade level in second grade but doesn’t understand math,” Mathnasium of Denton owner Beena Momin said. “Because of that gap, they’re kind of shy and closed in. We see that as a trend a lot. Confidence is an issue.”